Whatever kind of physics may be found at the LHC, strongly-interacting particles will be involved and therefore quantum chromodynamics will play a crucial role. For processes at high energy scales, perturbation theory remains the most powerful approach. These lectures will review the foundations and limitations of perturbative QCD and its application to high-energy processes, including jet production and fragmentation, deep inelastic scattering, and heavy quark and Higgs boson production.